North Korea replied that that it considered bombing Guam, a US island in the Pacific with an important military base.

Ray insisted that "lasting peace and denuclearisation of the Korean peninsula must be achieved through peaceful means" and that "this excludes military action."

But she insisted on EU's condemnation of North Korea's "outright violation" of its international obligations and said Pyongyang must "refrain from any further provocative action that could increase regional and global tensions."

"The EU will continue to put pressure on DPRK," she said, using the acronym for Democratic Popular Republic of Korea, the official name of the communist dictatorship.

The EU spokeswoman said that the EU "expects" North Korea "to engage in credible and meaningful dialogue," and that the EU is "ready to support such dialogue."

She added that EU's high representative, Federica Mogherini, held several bilateral meetings about the issue at a summit of Asean, the Association of Southeast Asian Nations, including with the foreign ministers of the US, China, Russia and South Korea.

On Wednesday, the US secretary of state, Rex Tillerson, said that Trump wanted to "send a message" to North Korean leader Kim Jong-Un to help him "avoid any miscalculation" about US intentions.

He added that there wasn't "any immediate threat" and that "Americans should sleep well at night."

Trump himself said on Twitter that he hoped that "we will never have to use this [nuclear] power, but there will never be a time that we are not the most powerful nation in the world!"

Wednesday marks the 72nd anniversary of the nuclear bombing of Nagasaki by the US on 9 August 1945, three days after Hiroshima was also bombed.

In Paris, the French government spokesman, Christophe Castaner, said that Trump expressed a "determination" that "all US presidents would have had, because they cannot accept that a part of their territory can be targeted by nuclear ballistic missiles."

But he added that the France was "preoccupied" by the situation and called on "on all sides to act responsibly."

In Berlin, a foreign ministry spokesman said that the German government was watching the "increasing rhetorical escalation … with the greatest concern" and called "on all sides to use restraint."

He insisted that a "military option" could not be "the answer in the quest for a nuclear weapon-free" Korean peninsula.

Meanwhile, European markets were losing ground amid concerns over the situation. In the early afternoon, London's FTSE index was down 0.6 percent, Frankfurt's Dax down 1.16 percent and Paris's Cac down 1.46 percent.

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